This is a cooperative project to isolate, identify, and study the biological and chemical properties of cardiac stimulants found among certain species of the phylum, Coelenterata, from the Pacific. Crude extracts of nine species of only thirteen tested have shown some degree of a positive inotropic effect on isolated rabbit and rat auricles. One drug, partially purified from Anthopleura xanthogrammica extracts has been studied in some detail. The plan is to isolate the activity agents by appropriate techniques; e.g., gel permeation, ion exchange, and adsorption chromatography have been found useful. Separations are monitored by bioassays with isolated rat or rabbit auricles. The purified agents will then be characterized and identified by chemical and spectroscopic techniques including Fourier transform nmr. They will also be subjected to experiments to clarify the mechanism of action on the cardiac muscle and delineate potential practical utility.